The present invention relates to an endless chain for the traveling web transport assembly of a textile machine such as a tenter frame.
One known arrangement for transporting a web of textile material through a tenter frame includes a pair of assemblies that include a pair of spaced endless chains, each supporting a plurality of web engaging members, such as vertical needles, onto which one edge portion of the textile web is impaled. The assemblies include a plurality of hub members, each hub member receiving a pin member therein and connected by a link to an adjacent hub member, with each pin member connected by a link to an adjacent pin member so that the hub links and the pin links are arranged in an alternating manner.
To guide an endless chain during its travel, each hub member is typically provided with a guide roller element rotatably secured thereto concentric with the associated pin member. Each guide roller element includes a ball bearing assembly for permitting rotation of the guide roller element relative to the hub member within a roller track extending in the direction of travel of the endless chain. The guide roller elements and the roller track cooperate together to support the endless chain with respect to the force exerted thereon by the textile web in a direction transverse to the direction of movement of the endless chain.
The ball bearing assembly of each guide roller element must be cyclically lubricated during normal operations and, for this purpose, it is known to provide a lubrication arrangement including a bore extending axially in each pin member and a radial bore extending from each axial bore to the outer circumference of the pin member. Each hub member includes a bore extending radially with respect to the axis of the respective pin member received therein and generally aligned with the radial bore in the pin member. Additionally, if the hub member is provided with a bushing for rotatably supporting the pin member in the hub member, the bushing is also provided with a radial throughbore. Accordingly, lubricant can be introduced into the ball bearing assembly through the respective aligned bores in the pin member, the bushing and the hub member.
To facilitate efficient lubrication of the ball bearing assemblies, one known practice includes securing each hub member, bushing and pin member against movement relative to one another so that their respective bores remain in alignment. However, in such an arrangement, the bushing tends to be subjected to uneven wear during direction reversing movement of the endless chain about the drive rollers on which it is trained. Thus, the bushing tends to wear out quicker than if the wear were uniformly distributed. Accordingly, the need exists for an endless chain for a traveling hub transport assembly having a ball bearing assembly which is easily and reliably accessible for introducing lubricants thereto.